Promoting, maintaining, and repairing the condition of skin is important for medical and cosmetic reasons. For example, factors such as humidity, ultraviolet rays, cosmetics, diseases, stress, traumas, and eating habits can affect skin and cause various skin problems. Skin can also become less resilient with age, as is illustrated by the formation of wrinkles. Thus, agents that help to promote, maintain and repair the condition of skin are needed.
Skin contains an elaborate network of elastin fibers responsible for maintaining the skin's elastic properties. However, in response to various factors such as excessive exposure to sunlight, the elastic fiber system becomes hyperplastic, disorganized and ultimately disrupted. This process is known as actinic elastosis, and it is a principal cause of wrinkling, discoloration and laxity of the skin. However, as new fibroblasts, endothelial cells and keratinocytes form, the skin can repair itself. Unfortunately, the skin becomes less able to do so as it ages. Therefore, agents that can accelerate the growth and repair of skin, for example, of prematurely aged skin, are needed.
Fibronectin, a glycoprotein, is involved in many cellular processes including tissue repair, embryogenesis, blood clotting, cell migration, wound repair, and cell adhesion. There are 2 main forms of fibronectin: (1) an insoluble glycoprotein dimer that serves as a linker in the extracellular matrix (ECM); and (2) a soluble disulfide-linked dimer found in the plasma. The ECM form of fibronectin is made by fibroblasts, chondrocytes, endothelial cells, macrophages and certain epithelial cells. The plasma form of ECM is made by hepatocytes. Fibronectin can serve as a general cell adhesion molecule by anchoring cells to collagen or to proteoglycan substrates. Fibronectin can also organize cellular interactions by binding to components of the ECM and to membrane-bound fibronectin receptors on cell surfaces. Fibronectin is also important in cell migration during embryogenesis and has been implicated as a protein important in mediating the anti-wrinkle and skim-firming effects of various treatments (Chi et al., (2002)).
Therefore, agents and compositions that increase in the amount of fibronectin in tissue are needed to maintain, promote and repair the condition of skin. Such agents and compositions would be useful to treat, rejuvenate and restore the condition of aged skin.